CD Mats -- do they work? Are they dangerous?

I use the SID branded one that is green color and have used it in several different CDP's and DVD players with no operational issues. Whether or not they are beneficial is in the ear of the beholder. Like most tweaks, the benefits of these devices are modest, at best, in my opinion and they will certainly not transform your system from an ugly duckling to a swan. If you are otherwise happy with your system and looking for that extra 2-5% that most tweaks are intended to provide, they may be worth trying. Based on my experience I wouldn't pay the price of that carbon fiber one though. I would suggest trying one of the cheaper ones first.

I'm not sure they're all voodoo. There are several companies - Esoteric, Electrocompaniet and maybe others, who feel that clamping the full surface of the disc is a better way to go than just in the center. So, from a mechanical standpoint, the CD mat may accomplish that goal to some degree. I've tried them, but I haven't really spent any time doing A/Bs. I don't think they're "dangerous" in most players, but some players, such as the Esoteric X-05, specifically tells you not to use it, perhaps due to its full-clamping transport. I would also hesitate to use it on some "puck" players, such as Naim, where the extra layer of material may weaken the magnetic bond, causing the puck to fly off and into the machine during play.

123,

Have you tried that carbon fiber one?

No, I haven't tried the carbon one.